1. Field of the Invention
The invention relates in general to an output card suitable for interfacing a load with the central processing unit of a computer or microprocessor controller and more particularly to an output card having a solid state current sink with an electronic circuit breaker.
2. Description of the Prior Art
Conventional fuse and circuit breakers comprise a resistive element that is sized to either melt, in the case of a fuse, or heat up to trip the circuit breaker under predetermined current conditions. The heating of the resistive element before the conventional fuse or circuit breaker disconnects the circuit from the load generally requires an appreciable time interval on the order of 50.times.10.sup.-3 seconds. In the case of a fuse another disadvantage is its maintenance cost. A stock of fuses must be inventoried for replacement and maintenance time is increased for the physical replacement of the fuse. Another disadvantage for both the fuse and circuit breaker is that upon disconnection, often times the operator has no way of knowing that the fuse has melted or the circuit breaker has tripped. Accordingly it would be desirable to have a fast acting electronic circuit breaker that may be reset by a simple switch and would give an indication when the electronic circuit breaker has been triggered and in addition an indication when the circuit is in proper operation. Furthermore it would be desirable for the electronic circuit breaker to incorporate a current sink i.e. a "current sink" output. A "current sink" output is technological shorthand for "providing a current path back to the supply or zero potential point".